Conversation

Notices

1. Embed this notice
   :debian: 𝚜𝚎𝚕𝚎𝚊 :opensuse: (selea@social.linux.pizza)'s status on Thursday, 07-Sep-2023 23:28:36 JST :debian: 𝚜𝚎𝚕𝚎𝚊 :opensuse:

   Am I the only person who does not see the benefit of using LVM on a Virtual Machine?

   It makes somewhat sense on a physical machine, but not on a VM in my world.

   #linux #lvm #vm

   • Embed this notice
     feld (feld@bikeshed.party)'s status on Thursday, 07-Sep-2023 23:28:34 JST feld

     in reply to
     If you want to make a snapshot on ext4/xfs/whatever, yeah, you kind of need it
   • Embed this notice
     feld (feld@bikeshed.party)'s status on Thursday, 07-Sep-2023 23:30:01 JST feld

     in reply to

     • feld
     I'm in a situation right now where I have a VM that I need to pause a database/index service and run a backup as quickly as possible, but it's like 800GB and I can't LVM snapshot because the OS image/template didn't use LVM...
     
     I could have scripted it to take a snapshot, mount the filesystem somewhere, read the data from there, unmount, destroy snapshot
     clacke likes this.
   • Embed this notice
     feld (feld@bikeshed.party)'s status on Thursday, 07-Sep-2023 23:33:06 JST feld

     in reply to
     on EC2? They are not very instant. The docs say they're "instant", but then it's pending while it streams the blocks to S3 which takes a long time.
     
     And then I'd have to orchestrate restoring that snapshot to a EBS volume, mounting that somewhere, and reading the data off.
     
     And you get to pay for all the data transfers back and forth haha 🥲
     clacke likes this.
   • Embed this notice
     :debian: 𝚜𝚎𝚕𝚎𝚊 :opensuse: (selea@social.linux.pizza)'s status on Thursday, 07-Sep-2023 23:33:08 JST :debian: 𝚜𝚎𝚕𝚎𝚊 :opensuse:

     in reply to

     • feld

     @feld

     You can make a snapshot of a VM

   • Embed this notice
     feld (feld@bikeshed.party)'s status on Thursday, 07-Sep-2023 23:42:29 JST feld

     in reply to
     We have the capability of running everything including managing our own datacenter/rackspace, but the goal is to keep the team small so we gotta outsource some of the infrastructure or we won't have any time to do the interesting bits
     
     I really really miss having my own server hardware, storage, and network gear that goes at full capacity all the time.
     
     EC2 really punishes you, especially on disk IO. Sometimes I literally download huge things to my own server at home because I have large capacity NVMEs and 5gbit internet, then I upload it to our S3 or whatever as needed
   • Embed this notice
     :debian: 𝚜𝚎𝚕𝚎𝚊 :opensuse: (selea@social.linux.pizza)'s status on Thursday, 07-Sep-2023 23:42:31 JST :debian: 𝚜𝚎𝚕𝚎𝚊 :opensuse:

     in reply to

     • feld

     @feld

     Ah I have touched AWS a couple of times and I hated every minute of it.

     Yeah, then I understand

   • Embed this notice
     tokudan@chaos.social's status on Friday, 08-Sep-2023 00:25:01 JST tokudan

     in reply to

     @selea I'd say it depends on the type of VM.
     If it's a throwaway-and-rebuild-on-change machine, LVM is irrelevant.
     If it's a VM that's aging like fine wine and I can't just rebuild it within 5 minutes, I'll probably be happy if I use LVM at some point, even if it's just saving me a reboot to resize a mounted partition that's in use.

     That's why my VMs still get LVM by default, unless I've already designed the rebuild machinery.

     clacke likes this.
   • Embed this notice
     tokudan@chaos.social's status on Friday, 08-Sep-2023 00:25:31 JST tokudan

     in reply to

     @selea that's news to me, I remember messages from the linux kernel after partprobe -s refusing to reload a partition table because one of the partitions is in use.
     If that's changed now, great...

     clacke likes this.
   • Embed this notice
     :debian: 𝚜𝚎𝚕𝚎𝚊 :opensuse: (selea@social.linux.pizza)'s status on Friday, 08-Sep-2023 00:25:33 JST :debian: 𝚜𝚎𝚕𝚎𝚊 :opensuse:

     in reply to

     • tokudan

     @tokudan

     Every those that is being in use

   • Embed this notice
     :debian: 𝚜𝚎𝚕𝚎𝚊 :opensuse: (selea@social.linux.pizza)'s status on Friday, 08-Sep-2023 00:25:35 JST :debian: 𝚜𝚎𝚕𝚎𝚊 :opensuse:

     in reply to

     • tokudan

     @tokudan

     You actually can resize the partition without rebooting and/or using LVM :)

   • Embed this notice
     :debian: 𝚜𝚎𝚕𝚎𝚊 :opensuse: (selea@social.linux.pizza)'s status on Friday, 08-Sep-2023 00:25:38 JST :debian: 𝚜𝚎𝚕𝚎𝚊 :opensuse:

     in reply to

     • tokudan

     @tokudan

     Basically, after adding the extra storage in our hypervisor, you need to perform a rescan of the disk:

     echo 1 > /sys/class/block/sda/device/rescan

     Then you can resize it with tools like "cfdisk". And what that is done - resize the filesystem with

     resize2fs -p /dev/sda1

     clacke likes this.